Aperture Printing, a film processing lab in central London, has released a limited-edition black-and-white slide film called Euston 400.
The film is a repackaged black-and-white negative film produced by Rollei that can be turned into positives thanks to a new development process created by one of the lab’s staff members.
A small batch of Euston 400 has been produced for the film’s official launch and can be bought direct from the lab, on London’s Rathbone Place.
The new film – which is based on Rollei 400 – is the brainchild of Alex Cole, a developer who joined the London processing lab earlier this year. Euston 400 is expected to be the first in a range of black-and-white films that can be shot as slide and processed via the lab’s new proprietary developer.
Black-and-white slide is not a new idea: in the 1990s, Agfa previously produced Dia, a 12-ISO slide film, until the 1990s, until it was superseded by the much more popular Scala 200X, which survived until 2005.
German film producer Adox released a version of its HR-50 film, which is on a clear acetate base, called Scala 50 in 2019.
Cole told Kosmo Foto: “This project has been in mind for a long time. I started experimenting with black-and-white reversal kits from Bellini and Adox in 2023. These kits made the process accessible, but I struggled to get consistent results due to the chemistry quickly becoming exhausted.
“I joined Aperture Printing at the start of February. The project was restarted with the intention of producing our own reversal chemistry. Film testing started in March.”
Cole said getting the chemical process right – and scaleable to a lab setting – was a gradual process.
“There are a lot of online resources and enthusiasts that have been incredibly useful for learning the chemistry and basic process,” he said. “The difficulty came from translating the process into one that is sustainable in a commercial setting without the knowledge or machinery used when black-and-white reversal was last publicly available.
“Understanding the chemistry and mechanisms of black-and-white reversal has been a personal research project since 2023. Testing of the process didn’t start until March 2025. Each chemical stage was tested individually to give a whole understanding of the process. Our reversal recipe has successfully developed 50+ black-and-white slide films.”
Cole said the lab already had plans to release two more reversal films, also based on Rollei black-and-white emulsions.
“The high silver content and clear bases produce bright slides with incredible tonal range. Each film has different characteristics as a slide film. The variety of ISO speed allows the films to be shot in a range of environments.”
Cole said more films may be rebranded in the future, as experiments with other emulsions have been promising.
“The plan is to be able to reverse as many currently produced clear-base black-and-white films as possible. So far we have had great results with the Rollei range: Retro 400S, Retro 80S, Superpan 200, Infrared, RPX 25, as well as Adox Scala 50 and Washi F.”
Cole said the lab had produced 60 rolls of Euston which are available now. The film costs £8 per roll, with development costing £20 and development and scanning £26.
Kosmo Foto was given a roll of the film to test ahead of the release, which we tested on a Leicaflex on a trip to Germany in June. You can see example pictures from it below, which were developed and scanned by Aperture Printing. (Note: Kosmo Foto holds its Cameraburo pop-ups at Aperture Printing, but was offered this test roll along with several other London film photographers.)
I'm a New Zealander who has been living in London since the mid-1990s, shooting film seriously since the year 2000. Kosmo Foto was launched in 2012 and has since become a film brand, with the release of my first films Kosmo Foto Mono 35mm (2017) and Kosmo Foto Mono 120 (2019).
I’m doing everything I can to promote film photography in the 21st Century, and help it survive and thrive. If you want to write something for Kosmo Foto, please drop me a line at foto.dowling@gmail.com.
